张鹏超，宋崇林，吴兆阳，吕刚.DPF主动再生过程中缸内远后喷策略对柴油机排放及DOC升温特性的影响[J].内燃机工程,2018,39(3):45-52.
DPF主动再生过程中缸内远后喷策略对柴油机排放及DOC升温特性的影响
Influence of Last-Post-Injection Strategy on Exhaust Emissions and Temperature Rise Behaviour of a DOC During DPF Active Regeneration
DOI：10.13949/j.cnki.nrjgc.2018.03.007
关键词:柴油机  远后喷  排放  柴油机氧化催化器
Key Words:diesel engine  last-post-injection  emission  diesel oxidation catalyst
基金项目:国家重点基础研究发展计划项目（2013CB228502）
作者单位
张鹏超，宋崇林，吴兆阳，吕刚 天津大学 内燃机燃烧学国家重点实验室，天津 300072 
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摘要:在一台高压共轨柴油机上，研究了用于颗粒捕集器(DPF)再生的缸内远后喷策略对发动机排放、油耗率及柴油机氧化型催化器(DOC)升温特性的影响。结果表明，碳氢化合物（HC）和一氧化碳（CO）排放浓度均随后喷油量的增加而升高，HC排放浓度随着后喷定时的延迟先升高后稳定，而CO排放浓度则先升高后降低；氮氧化物（NOx）和碳烟排放均随后喷定时的延迟呈现先降低后升高的趋势，远后喷的引入使NOx排放降低了9.8%～24.0%，NOx排放浓度随后喷油量的增加而降低，而碳烟排放浓度在后喷定时小于70°时随后喷油量的增加而降低，在70°后则相反；后喷油量为14、17mg,而后喷定时在上止点后80°～140°范围的远后喷工况下，DOC后排气温度均可达到DPF主动再生温度600℃；DOC能量利用率随后喷油量的增加而升高，随后喷定时的延迟先升高后保持稳定，后喷定时在80°～140°范围内的DOC能量利用率保持在62.73%～75.75%之间，且在上止点后100°时刻达到最大能量利用率。研究结果为缸内远后喷DPF再生及其控制策略的发展提供了有价值的理论依据。
Abstract:The influence of the last-post-injection strategy on the exhaust emissions, brake specific fuel consumption and the temperature rise behaviour were investigated on a diesel engine. Results show that both HC and CO emissions increase with the rise of post injection quantity. With the delay of post-injection timing, the HC emissions reach stable condition after initial increase, and the CO emissions decrease after initial increase. While the emissions of NOx and soot tend to decrease first and then increase moreover, the NOx emissions decrease by 9.8%～24.0% with last post injection and reduce with the increase of post injection quantity, while the soot emissions decrease with the delay of post injection timing of less than 70° after TDC, but show an opposite trend with more than 70° after TDC. The temperature of exhaust gas after the DOC can reach over 600 ℃ for DPF active regeneration when the post injection quantity is 14 mg or 17 mg with the injection timing of 80 to 140° after TDC and the maximum temperature at 100° after TDC. The energy efficiency of the DOC increases with the rise of post-injection quantity, and reaches stable conditions after initial increase with the delay of post injection timing. The energy utilization efficiency of DOC is within the range of 62.73% to 75.75% when the post injection timing is 80° to 140° after TDC, thus leading to a maximum energy efficiency of DOC at 100° after TDC. The results provide a valuable information for the development of DPF regeneration and control strategy.
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